1. Field of the Invention
This invention relates to wire anodizing, and, more particularly, to a high speed aluminum wire anodzing machine and process.
2. Description of the Prior Art
In recent years, there has been a rapid increase in the commercial use of anodized aluminum wire, strip stock and the like. This is especially true in the electrical equipment industry as a substitute for increasingly expensive copper wire. In addition, the dielectric properties of the anodizing have been found to be preferred over other types of dielectric wire coatings.
In the anodizing of aluminum wire and the like, a protective oxide film is formed on the metal by passing an electric current through a bath or eletrolyte in which the metal is suspended and through which it passes. Although the general process of anodizing is well known and in commercial use, current methods are slow and problematical. For example, one of the most common means of anodizing aluminum wire and the like is to pass the wire through a very long anodizing tank. In order to achieve sufficient retention time of the the wire in the tank to yield the desired anodized coating, the wire is run very slowly through the tank at a speed on the order of 20 feet per minute. Because of the very slow speed of this process, the cost of anodized wire produced by this type of process is unduly high.
Although attempts have been made to speed up the process of anodizing aluminum wire and the like, the results have been unsatisfactory. For example, the anodizing resulting from these attempts at increasing the speed of the process have included cracking and flaking of the anodizing, poor adherence, and incomplete coverage and eratic coating thicknesses.
Accordingly, there is a current need for a high speed means to anodize alumunum wire which will produce uniform anodized coating with complete wire coverage.